Is there anyway to open up the applications menu with only the windows key, and not the Windows+Space Bar?
You can't do that through the custom shortcuts that you can set via Switchboard, which only allow combinations of 2 or more keystrokes.
I believe it is possible using xbindkeys, though. To install it (along with a GUI configurator) paste this command into a terminal window:
sudo apt-get install xbindkeys-config
In order to run, the program needs a config file in your home directory. Create it with this command:
xbindkeys --defaults > /home/YOURUSERNAME/.xbindkeysrc
Now run the program by typing
xbindkeys-config into the terminal or in the search string of the application launcher. This window will fire up:
Hit "New" to create your custom command. On the top right box you must type in all relevant information: a name for the shortcut, the key assigned to it, and the command to execute the program (in your case
slingshot-launcher). To get the name of the correct key use the "Get Key" button. A blank window will pop up. Just press your key and the program will automatically record its name code. Hit "Save & Apply & Exit" and you're done.
Now the bad news: in my test I couldn't assign the Super key. I'm afraid it is already binded to other shortcuts, but I couldn't troubleshoot the issue. I was able to assign a "less-used" key, though, like the "Pause" key.
Note. To make this setup permanent you need to add
xbindkeys to your startup applications.